Telephone line monitoring circuit for providing a visual and auditory signal if the telephone line becomes inoperative

ABSTRACT

A telephone line monitoring apparatus which is used to continuously monitor the telephone line and provide both a visual signal and an auditory signal if the line becomes inoperative. The circuit is designed to be plugged into a conventional telephone jack and monitor the line voltage so that if the line voltage falls below about 6 volts DC or if the line is short circuited or becomes disconnected, the telephone line monitoring apparatus will cause a light emitting diode to flash on and off and further will cause an auditory sounder to emit an audible signal. The light emitting diode is a self-flashing type which serves to modulate the auditory signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of consumer telephone linemonitoring apparatus which is used by the consumer to monitor theincoming telephone line to be certain that the line is operative.Oftentimes, an individual who may be waiting for an important telephonecall has no idea that the telephone line has gone dead. Unless theindividual tries to make a call and discovers that the line isinoperative, there is no way for the consumer to know of this. Thepresent invention relates to the field of monitoring and signallingdevices which can detect line failure and further provide both a visualsignal and an auditory signal to alert a user of the problem with theincoming telephone line.

2. Description of the Prior Art

In general, line monitoring devices have been produced in the prior art.The following patents are representative of known telephone linemonitoring devices:

1. U.S. Pat. No. 4,841,559 issued to Curtis on June 20, 1989 for"telephone Network Interface Tester".

2. U.S. Pat. No. 4,513,176 issued to Fostveit on Apr. 23, 1985 for "TestApparatus For Telephone Equipment".

3. U.S. Pat. No. 4,827,498 issued to Ross on May 2, 1989 for "TelephoneLine And Instrument Tester".

4. U.S. Pat. No. 3,976,849 issued to Champan on Aug. 24, 1976 for"Telephone Wiring Tester".

5. U.S. Pat. No. 4,544,807 issued to Sers on Oct. 1, 1985 for "FaultDetector Test Instrument".

6. U.S. Pat. No. 3,951,248 issued to Feiner et al on Apr. 20, 1976 for"Telephone Line Visual Status Indication Circuit".

7. U.S. Pat. No. 4,002,861 issued to Putt on Jan. 11, 1977 for"Protector Module Test Set".

8. U.S. Pat. No. 4,373,120 issued to McDonald on Feb. 8, 1983 for "LineTest Termination Device".

9. U.S. Pat. No. 4,564,728 issued to Romano on Jan. 14, 1986 for"Apparatus For Testing A Telephone Line".

10. U.S. Pat. No. 4,588,862 issued to Grabowy on May 13, 1986 for"Visual Display Network Interface".

11. U.S. Pat. No. 4,600,810 issued to Feldman et al on July 15, 1986 for"Telephone Line Tester".

U.S. Pat. No. 4,827,498 issued to Ross relates to a telephone linetester which has a standard modular plug that can plug into a standardtelephone line. The circuit of the tester is responsive to the flow ofcurrent therethrough for providing an indication of the operation of thesource related equipment and/or the telephone instrument. The device isnot a continuous monitoring device and requires that the user unplug thetelephone and insert this plug into the line in place of the telephoneline and then do the testing.

U.S. Pat. No. 3,976,849 issued to Champan illustrates a telephone wiringtester designed to receive modular terminal plug 17 and to test linevoltage. This device also is not a continuous monitoring device and is atest device which is used when the telephone is unpluged. The device isused to test and check for the presence of a minimum voltage of thecorrect polarity between the tip and ring line conductors of a telephoneinstallation and also to check for the presence of a proper AC lampvoltage between the ground and the lamp lead on a modular jack typetelephone installation.

U.S. Pat. No. 4,544,807 issued to Sers discloses a fault detector testinstrument for detecting faults on telephone lines. The device providesan indication of the most common wiring faults such as grounds, foreignE.M.F., resistance across the lines, open circuits, etc.

U.S. Pat. No. 4,513,176 to Fostveit shows a test apparatus for telephoneequipment. The device discloses a multiplicity of test circuits that theowner can use to test for a problem in the line.

U.S. Pat. No. 4,841,559 to Curtis discloses another telephone test linetype device.

U.S. Pat. No. 3,951,248 to Feiner discloses a telephone visualindicating circuit to enable an installer to determine without actuallyphysically going off the hook what the status of a telephone line is.

U.S. Pat. No. 4,002,861 issued to Putt discloses a modular plug-intelephone test set in a carrying case.

U.S. Pat. No. 4,373,120 to McDonald discloses a line test device used bythe telephone company to test the telephone line. It provides acharacteristic signature recognizable by the telephone central officewhen a continuity test is made on the subscriber line.

U.S. Pat. No. 4,564,728 to Romano discloses another embodiment of atelephone line tester. This tester is a simple device which uses abipolar LED comprised of two parallel light emitting diodes which arearranged between terminals 15 and 16 in opposite polarity. The telephoneline tester comprised of this bipolar LED has coupled thereto two wireswhich terminate in a modular plug. The plug is inserted into thetelephone jack and if the telephone line is operating properly, one ofthe diodes will illuminate depending upon the polarity of the lines.

U.S. Pat. No. 4,588,862 to Grabowy is a visual display network interfacefor placement between incoming telephone network access lines to astructure and the user telephone equipment within the structure.

U.S. Pat. No. 4,600,810 to Feldman is another telephone line testerwhich determines whether or not there is adequate power in the signalwhen plugged into the telephone jack.

Overall, there are numerous telephone line testing apparatus but most ofthe prior art testing apparatus does not provide continuous monitoringof the line and is instead an intermittent test apparatus which requiresdisconnecting the telephone and then testing the line. Continuousmonitoring is important for the average consumer who does not know whenhis or her line may go dead. In addition, for a blind person, a visualsignal is not adequate to warn when the line has gone dead and asupplemental auditory signal is required. In addition, the telephone inthe household may only be in one room and the person may not be lookingat the telephone for an extended period of time. Therefore, an auditorysignal to warn of line failure is also important under normalcircumstances in case the telephone is not in easy view of the person.In addition, for a deaf person, an audible signal is not adequate towarn when the line has gone dead and a supplemental visual signal isrequired.

SUMMARY OF THE PRESENT INVENTION

The present invention is a telephone line monitoring apparatus which isused to continuously monitor the telephone line and provide both avisual signal and an auditory signal if the line becomes inoperative.

It is well known that the standard line voltage into a telephone line is50 volts and that under normal operation, 50 volts are required for thetelephone to ring when the number is dialed. When a local instrument isoff-hook and dial tone is heard, the 50 volts drops to nominally 6 to 8volts DC. If the telephone line is cut or shorted, there is no voltageand the line is inoperative. Accordingly, if the number of the telephoneis dialed, it will not ring.

It has been further discovered, according to the present invention, thatif a monitoring circuit is wired into the incoming telephone line, whichmonitoring circuit is capable of sensing the voltage across the incomingline and further provides an auditory and visual signal when the linevoltage drops below about 6 volts DC so as to make the telephone lineinoperative, then the monitoring system can warn a user when thetelephone line has become inoperative in this manner and thereby preventneedless waste of time and problems in waiting for a telephone call whenthe line is inoperative.

It has further been discovered, according to the present invention, thata continuous monitoring device provides a means wherein the user can beinstantaneously forewarned if the line goes dead.

It has additionally been discovered, according to the present invention,that the inclusion of both a visual signal and an auditory signal in themonitoring circuit provides an assured warning system since a visualsignal alone may not be sufficient if there is only one telephone whichis located in only one room and the telephone is not always in easyviewing of the user.

It has further been discovered, according to the present invention, thatthe continuous monitoring device can also be used with other telephoneline operating devices such as telecopiers, to warn when the telecopierline has gone dead.

It is therefore an object of the present invention to provide acontinuous monitoring device which continuously monitors the telephoneline for a telephone line operating device such as a telephone ortelecopier, and which provides both a visual and auditory signal if oneor both of the wires of a telephone line is cut or broken, or if thedevice is unpluged from the telephone line, or if the two telephonewires are shorted together. The monitoring device is also designed toprovide a warning signal if the line voltage drops below about 6 voltsDC to thereby make the telephone ring system inoperative.

It is a further object of the present invention to provide a visual andauditory signal only if the telephone line is cut or broken or unplugedor shorted and to not be activated during normal use of the telephone.It is an object of the present invention to provide such a device which,while continuously monitoring the line, will simultaneously permitordinary use such as an answering machine responding to an incomingcall, a person making a telephone call, a person answering the telephoneafter a ring, or if a computer answers or makes a call.

Further novel features and other objects of the present invention willbecome apparent from the following detailed description, discussion andthe appended claims, taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring particularly to the drawings for the purpose of illustrationonly and not limitation, there is illustrated:

FIG. 1 is a schematic diagram of the circuitry of the preferredembodiment of the present invention which has a nine-volt battery as thepower source.

FIG. 2 is a schematic diagram of the circuitry of an alternativeembodiment of the present invention which utilizes a standardalternating current source for power and includes an AC to DCtransformer, and further incorporates an adjustment wiring scheme toconnect the system to a computerized telephone and an interconnectingmeans to connect the system to an external burglar alarm or similarexternal warning device.

FIG. 3 is a diagrammatic and schematic illustration of the presentinvention monitoring device wired into an incoming line which is usedfor a telephone.

FIG. 4 is a diagrammatic and schematic illustration of the presentinvention monitoring device wired into an incoming line which is usedfor a telecopier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Although specific embodiments of the invention will now be describedwith reference to the drawings, it should be understood that suchembodiments are by way of example only and merely illustrative of but asmall number of the many possible specific embodiments which canrepresent applications of the principles of the invention. Variouschanges and modifications obvious to one skilled in the art to which theinvention pertains are deemed to be within the spirit, scope andcontemplation of the invention as further defined in the appendedclaims.

Referring to FIG. 1, there is shown at 10 the schematic diagram of thecircuitry of the preferred embodiment of the present inventionmonitoring device. Lead wires 12 and 14 connect to the incoming twotelephone wires. Either lead wire 12 or 14 can connect to the ringincoming wire and the other of the lead wires can connect to the tipincoming wire. The two lead wires 12 and 14 connect to a bridge circuit16 made up of four diodes 18, 20, 22 and 24, or a single unit bridgeassembly. Either polarity of the phone line may be attached. By way ofexample, the diodes may be rectifier diodes. One output of the bridgecircuit 16 goes to wire 30. The other output of the bridge circuit 16goes to resistor R1. The output of the bridge going to resistor R1 isalways a positive voltage, independent of the polarity of the voltage onthe phone line; independent of the existence of a ringing signal; andalso independent of "on-hook or off-hook" condition of the localinstrument such as a telephone. This positive voltage is lost when thetelephone line is no longer connected or is shorted. Resistor R1 limitsthe quiescent current drawn from the phone network, and also limits thebase current into transistor Q1. Resistor R1 is wired in series withresistor R2 and then both are connected to transistor Q1. Resistor R2provides a defining reference to the semi-conductor connection of bridgediodes and Q1 base. Without R2 the alarm output could be erratic insteadof defined and regular. R2 also discharges any capacitance at the baseof Q1 when the phone line is no longer connected or is shorted. By wayof example, Resistor R1 may be a 1 megohm, 1/4 watt, 5% resistor andresistor R2 may be a 2 megohm resistor.

Transistor Q1 is a high input-impedance emitter-follower. It's emitteris normally positive and provides base current to Q2 through resistorR3. Resistor R3 is wired in series with the emitter of transistor Q1.Resistor R3 is also wired in series with resistor R4 and both resistorsare connected to transistor Q2. Resistor R4 provides a definingreference to the semi-conductor connector of Q1 emitter and Q2 base.Without R4 the alarm output could be erratic instead of defined andregular. Resistors R3 and R4 may each be a 1 megohm, 1/4 watt, 5%resistor.

Transistor Q2 operates as a switch. Normally the current from Q1 holdsQ2 saturated or ON so that its' collector voltage is low. Resistor R5 iswired in series with transistor Q2. Current through resistor R5 and atiny current through transistor Q1 and resistor R3 are drawn from thevoltage source 50 which by way of example may be a 9 volt battery. Thecollector of transistor Q2 goes high when the telephone line is nolonger connected or is shorted, and drives the emitter of Q3 high.Resistor R5 may be a 1 megohm, 1/4 watt, 5% resistor.

The base of transistor Q3 is wired in series to the collector oftransistor Q2. Transistor Q3 is also wired in series with resistor R6which in turn is connected to the light emitting diode 60. Transistor Q3is an emitter-follower. It's emitter is normally low, so almost novoltage is applied through resistor R6 to the light emitting diode 60.Thus the light emitting diode 60 is normally off. Resistor R6 may be a470 ohm resistor. The emitter of Q3 rises to a voltage of about 8 voltsDC when the phone line is no longer connected or is shorted. At thisvoltage, the current through the light emitting diode 60 is limited byresistor R6. The light emitting diode 60 is a self-flashing type. Whenit flashes ON, the voltage across the light emitting diode 60 drops toabout 1 volt DC to 1 1/2 volt DC. When the light emitting diode 60 turnsOFF, the voltage across the light emitting diode 60 rises to about thesame voltage as the emitter of transistor Q3. The light emitting diode60 flashing helps draw attention to the alarm condition.

Resistor R6 is wired in series to resistor R7 which in turn is wired inseries to transistor Q4. Resistor R7 may be a 22 kilohm resistor.Transistor Q4 is in turn wired in series with resistor R8 which in turnis wired in parallel with an auditory sounder 70. Resistor R8 may be a10 kilohm resistor. When the phone line is connected, the voltages atthe emitter of Q3, and also across the light emitting diode 60, arealmost zero. Thus the emitter of the emitter-follower Q4 is also atalmost zero volts, and the auditory sounder 70 remains silent. When thelight emitting diode 60 begins to flash on and off, the voltage acrossthe light emitting diode 60 is applied to resistor R7. Resistor R7limits the current into the base of emitter-follower Q4. Due to the riseand fall of voltage across the light emitting diode 60, the auditorysounder 70 is modulated louder and softer to help draw attention to thealarm condition. It is significant that the flashing of the lightemitting diode 60 is used as an up-down signal to modulate the auditorysounder 70. This saves the cost of a separate up-down or on-off circuitor device such as the 555 IC. Therefore reliability is greatly increaseddue to a reduced component count, and the battery drain is reducedsignificantly.

In the preferred embodiment, the components are wired to a 9 voltbattery 50, as shown. Wire 30 leads to the positive terminal of thebattery 50 while wire 80 leads to the negative terminal. Power for theflashing light emitting diode 60 and the modulated auditory sounder 70is taken from the 9 volt battery 50. Any 9 volt battery can be used.However, longest battery life will result from using long-life batteriessuch as the Duracell Alkaline Battery®.

The light emitting diode 60 flashes and the auditory sounder 70 ismodulated to help draw attention to the alarm condition. If a person ishard of hearing or deaf, the flashing light emitting diode 60 will bethe primary alarm. If the light emitting diode 60 becomes hidden behindan object, then the auditory sounder 70 will be the primary alarm to aperson with normal or adequate hearing. If the person is blind, then theauditory sounder 70 will be the primary alarm.

The present invention monitoring circuit 10 as described above providesmany significant advantages, including: (1) both visual and audiblealarms; (2) variable alarm signals to draw attention; (3) almostnegligible current drawn from the phone line; (4) low component countfor increased reliability; (5) audible alarm loud enough to be heardover normal ambient noises; and (6) use of a flashing light emittingdiode to modulate or vary the auditory sounder output therebyeliminating the requirement of a separate flasher circuit. In addition,the unit can be a self-standing unit and is of small size.

Referring to FIG. 3, in operation, the two lead wires 12 and 14 arewired into a standard telephone cable which ends in a normal telephoneplug 110. A dual telephone plug receptacle 120 is plugged into thefemale telephone receptacle 150 and the plug 130 from the telephone 140or telecopier 142 is plugged into one receptacle 124 of the dualtelephone plug receptacle 120 and the plug 110 from the presentinvention is plugged into the other receptacle 122. After the unit 10 isplugged into the telephone jack as just described, the unit 10 is openedand a 9 volt battery is installed and the device is closed. The userplaces the device on a surface, or uses conventional means such as twosided tape to mount the unit 10 on the telephone 140. Therefore, throughthis embodiment, the telephone line is continuously monitored.

As long as 50 volts is passing into lead wires 12 and 14, the output ofbridge 16 going to resistor R1 is always positive and the emitter fromtransistor Q1 continues to be positive and provides base current totransistor Q2 and resistor R3 and permits transistor Q2 to operate as aswitch and cause the sounder 70 and light emitting diode 60 to be in theoff position. Once the voltage falls below about 6 volts DC, or thecurrent is cut off or the line is shorted, then the positive voltagegoing from the bridge circuit 16 to resistor R1 is lost. With thisoccurrence, the collector of transistor Q2 goes high when the telephoneline is no longer connected or is shorted and this drives the emitter oftransistor Q3 high. Then the emitter of transistor Q3 rises to a voltageof about 8 volts direct current and causes the light emitting diode 60to begin flashing as previously described. When the light emitting diode60 begins to flash on and off, it applies a voltage across resistor R7which in turn limits the current into the base of emitter-followertransistor Q4 which in turn causes the auditory sounder 70 to becomeactivated. Due to the rise and fall of voltage across the light emittingdiode 60, the auditory sounder 70 is modulated louder and softer to helpdraw attention to the alarm condition.

Defined in detail, the present invention is a telephone line monitoringcircuit and apparatus, comprising: (a) circuit connector means forconnection into a telephone line jack at one end; (b) a bridge circuitincluding a first diode, a second diode, a third diode and a fourthdiode, the bridge circuit connected to said circuit connector means at alocation between the first and second diode and at a location betweenthe third and fourth diode; (c) a first resistor connected in series tosaid bridge circuit at a location between said second and third diodesuch that a positive voltage is transmitted from the bridge circuit tothe first resistor; (d) a second resistor connected in series to saidfirst resistor; (e) said first resistor and said second resistorconnected in series to the base of a first transistor which is a highinput-impedance emitter-follower; (f) the emitter of said firsttransistor connected in series to a third resistor; (g) said thirdresistor connected in series to a fourth resistor; (h) said thirdresistor and said fourth resistor connected in series to the base of asecond transistor; (i) said second transistor connected in series to afifth resistor; (j) a third transistor which is an emitter-followerconnected in series to said second transistor; (k) a sixth resistorconnected in series to the emitter of said third transistor; (l) a lightemitting diode connected in series to said sixth resistor; (m) saidsixth resistor connected in series to a seventh resistor which in turnis connected in series to the base of a fourth transistor; (n) theemitter of said fourth transistor connected in series to an eighthresistor; (o) said eighth resistor connected in parallel to an auditorysounder; (p) a voltage source connected in parallel to said fourthtransistor and said eighth resistor; (q) said bridge circuit at alocation between said first and fourth diodes, said second resistor,said fourth resistor, the emitter of said second transistor, said lightemitting diode, said auditory sounder, and said eighth resistorconnected to the negative terminal of said voltage source; and (r) saidfirst transistor, said fifth resistor, said third transistor, and saidfourth transistor connected to the positive terminal of said voltagesource; (s) whereby when said circuit connection means is connected to atelephone line, the telephone line monitoring circuit and apparatus candetect if the telephone line becomes inoperative and cause said lightemitting diode to provide a visual signal and said auditory sounder toprovide an audible signal if the telephone line becomes inoperative.

Defined broadly, the present invention is a telephone line monitoringcircuit and apparatus, comprising: (a) a circuit connector means forconnection into a telephone jack at one end; (b) said circuit connectormeans connected to a circuit means for providing a positive voltage to aresistor means which in turn provides a defining reference between thecircuit means for providing a positive voltage and a first transistormeans which is a high input-impedance emitter-follower with a normallypositive emitter; (c) the first transistor means connected to resistormeans which provides a defining reference between the emitter of saidfirst transistor means and the base of a second transistor means; (d)said second transistor means configured to act as a switch and toprovide a driving current to a third transistor means if the telephoneline becomes inoperative; (e) said third transistor means is an emitterfollower which energizes a light emitting diode and through resistormeans and a fourth transistor means also energizes an auditory sounder;and (f) a source of voltage to energize the circuit components; (g)whereby when said telephone line becomes inoperative, said circuit meansfor providing a positive voltage becomes inoperative to thereby causesaid second transistor means to provide a driving current to said thirdtransistor means which causes said light emitting diode to provide avisual signal and which also causes said auditory sounder to provide anaudible signal.

Defined even more broadly, the present invention is a telephone linemonitoring circuit and apparatus, comprising: (a) a circuit connectormeans for connection into a telephone jack at one end; (b) said circuitconnector means connected to a circuit means for providing a positivevoltage to a resistor means which in turn provides a defining referencebetween the circuit means for providing a positive voltage and a firsttransistor means which is a high input-impedance emitter-follower with anormally positive emitter; (c) said first transistor means connected totransistor means which acts as a switch and causes energy to flow past apoint in the circuit if the telephone line becomes inoperative, whichenergy activates a light emitting diode and through resistor means andadditional transistor means also energizes an auditory sounder; and (d)a source of voltage to energize the circuit components; (e) whereby whensaid telephone line becomes inoperative, said circuit means forproviding a positive voltage becomes inoperative to thereby cause thetransistor switch means to provide a driving current which causes saidlight emitting diode to provide a visual signal and which also causessaid auditory sounder to provide an audible signal.

Defined very broadly, the present invention is a telephone linemonitoring circuit and apparatus, comprising: (a) a circuit connectormeans for connection into a telephone jack at one end; (b) said circuitconnector means connected to a circuit means for providing a voltage toa resistor means which in turn provides a current into a firsttransistor means which is an emitter-follower; (c) the first transistormeans connected to resistor means which is connected between the emitterof said first transistor means and the base of a second transistormeans; (d) said second transistor means configured to provide a drivingcurrent to a third transistor means if the telephone line becomesinoperative; (e) said third transistor means energizes a light emittingdiode and through resistor means and a fourth transistor means alsoenergizes an auditory sounder; and (f) a source of voltage to energizethe circuit components; (g) whereby when said telephone line becomesinoperative, said circuit means for providing a voltage becomesinoperative to thereby cause said second transistor means to provide adriving current to said third transistor means which causes said lightemitting diode to provide a visual signal and which also causes saidauditory sounder to provide an audible signal.

Defined most broadly, the present invention is a telephone linemonitoring circuit and apparatus, comprising: (a) a circuit connectormeans for connection into a telephone jack at one end; (b) said circuitconnector means connected to a circuit means for providing a voltage toa resistor means which in turn provides a current into a firsttransistor means which is an emitter-follower; (c) said first transistormeans connected to transistor means which causes energy to flow past apoint in the circuit if the telephone line becomes inoperative, whichenergy activates a light emitting diode and through resistor means andadditional transistor means also energizes an auditory sounder; and (d)a source of voltage to energize the circuit components; (e) whereby whensaid telephone line becomes inoperative, said circuit means forproviding a voltage becomes inoperative to thereby cause transistormeans to provide a driving current which causes said light emittingdiode to provide a visual signal and which also causes said auditorysounder to provide an audible signal.

A second embodiment 10A of the present invention monitoring device isillustrated in FIG. 2. Most of the components in the second embodimentare the same as the first embodiment 10 with the addition of several newcomponents. A diode 160 is added in wire 80 and a Class II transformer170 with a 9 volt DC output is added into the circuit wires 30 and 80 sothat the device may be plugged into a standard alternating currentsource through Class II transformer 170. The diode 160 serves to blockthe battery 50 when the Class II 9-volt transformer 170 is plugged intothe alternating current source. Another addition to the circuit is aconnecting means to connect the circuit to an outside alarming devicesuch as a burglar alarm. Before a burglar breaks in, the burglar oftencuts the telephone line to abort the dialing out to the police orsecurity company by a silent alarm system. In this category ofinoperative telephone line, it is imperative to annunciate the facteither at a remote location or as a loud local sound such as a siren, orboth. The addition provides the present invention with the capability ofannunciating remotely or controlling remote devices. The addition ofresistor R9, transistor Q5, and relay K1 provides this capability. Whenan alarm is produced by the circuit as previously described, the emitterof Q3 goes from low to high. This condition causes the flashing lightemitting diode 60 to flash, and the sounder 70 to sound high and low,and now also provides current into the base of transistor Q5 throughresistor R9. This current switches Q5 from the OFF to the ON condition.The ON condition produces current through the coil of relay K1 toenergize K1 so that the single-pole single-throw contacts close. RelayK1 contacts are shown in the de-energized or open condition. Thisinvention also includes relays with a multiplicity of contacts whereinnormally closed contacts control other results. One such ancillaryresult might be a supervisory function associated with an overallsecurity installation. Relay K1 can be a light duty reed relay. Its'contacts could control external powerful relays whose contacts in turncontrol large loads such as sirens, banks or lights, etc. The system canalso comprise a manual switch 190 which shuts off resistor R9,transistor Q5 and relay K1. In this way, if the individual is at home,this portion of the system can be disarmed but when the individualleaves his home, this additional portion of the system can be armed. Tomake the system more versatile, a switch S1 can be added to provide aswitching means to different telephone line hook-ups. In a telephoneline, the red and green wires 14 and 12 respectively are for a normaltelephone or tip/ring line. The yellow and red wires 13 and 14respectively are used for a computerized phone system with no tip/ringline. A black wire in the phone line is not used. Accordingly, theswitch S1 permits either the normal telephone line or the computertelephone line to be used. In all other respects, the alternativeembodiment in FIG. 2 operates the same way as the preferred embodimentin FIG. 1.

Of course the present invention is not intended to be restricted to anyparticular form or arrangement, or any specific embodiment disclosedherein, or any specific use, since the same may be modified in variousparticulars or relations without departing from the spirit or scope ofthe claimed invention hereinabove shown and described of which theapparatus is intended only for illustration and for disclosure of anoperative embodiment and not to show all of the various forms ormodification in which the invention might be embodied or operated.

The invention has been described in considerable detail in order tocomply with the patent laws by providing full public disclosure of atleast one of its forms. However, such detailed description is notintended in any way to limit the broad features or principles of theinvention, or the scope of patent monopoly to be granted.

What is claimed is:
 1. A telephone line monitoring circuit andapparatus, comprising:a. circuit connector means for connection into atelephone line jack at one end; b. a bridge circuit including a firstdiode, a second diode, a third diode and a fourth diode, the bridgecircuit connected to said circuit connector means at a location betweenthe first and second diode and at a location between the third andfourth diode; c. a first resistor connected in series to said bridgecircuit at a location between said second and third diode such that apositive voltage is transmitted from the bridge circuit to the firstresistor; d. a second resistor connected in series to said firstresistor; e. said first resistor and said second resistor connected inseries to the base of a first transistor which is a high input-impedanceemitter-follower; f. the emitter of said first transistor connected inseries to a third resistor; g. said third resistor connected in seriesto a fourth resistor; h. said third resistor and said fourth resistorconnected in series to the base of a second transistor; i. said secondtransistor connected in series to a fifth resistor; j. a thirdtransistor which is an emitter-follower connected in series to saidsecond transistor; k. a sixth resistor connected in series to theemitter of said third transistor; l. a light emitting diode connected inseries to said sixth resistor; m. said sixth resistor connected inseries to a seventh resistor which in turn is connected in series to thebase of a fourth transistor; n. the emitter of said fourth transistorconnected in series to an eight resistor; o. said eighth resistorconnected in parallel to an auditory sounder; p. a voltage sourceconnected in parallel to said fourth transistor and said eighthresistor; q. said bridge circuit at a location between said first andfourth diodes, said second resistor, said fourth resistor, the emitterof said second transistor, said light emitting diode, said auditorysounder, and said eighth resistor connected to the negative terminal ofsaid voltage source; and r. said first transistor, said fifth resistor,said third transistor, and said fourth transistor connected to thepositive terminal of said voltage source; s. whereby when said circuitconnection means is connected to a telephone line, the telephone linemonitoring circuit and apparatus can detect if the telephone linebecomes inoperative and cause said light emitting diode to provide avisual signal and said auditory sounder to provide an audible signal ifthe telephone line becomes inoperative.
 2. A telephone line monitoringcircuit and apparatus in accordance with claim 1 wherein said voltagesource is a nine volt battery.
 3. A telephone line monitoring circuitand apparatus in accordance with claim 1 wherein said circuit connectormeans further comprises a pair of lead wires connected to a cable whichterminates in a telephone plug.
 4. A telephone line monitoring circuitand apparatus in accordance with claim 1 further comprising:a. a ClassII transformer with a 9 volt DC output connected to said secondresistor, said fourth resistor, the emitter of said second transistor,said light emitting diode, said auditory sounder, and said eighthresistor connected to the negative terminal of said voltage source atone input location and further connected to said first transistor, saidfifth resistor, said third transistor, and said fourth transistor at itssecond input location; and b. a fifth diode which is a blocking diodeconnected between said Class II transformer and said voltage source. 5.A telephone line monitoring circuit and apparatus in accordance withclaim 1 wherein said light emitting diode is a flashing light emittingdiode which modulates the signal of the auditory sounder as the lightemitting diode flashes on and off.
 6. A telephone line monitoringcircuit and apparatus in accordance with claim 1 further comprisingrelay means energized through a fifth transistor which in turn receivesits energy from said third transistor, to thereby connect the system toan external warning means.
 7. A telephone line monitoring circuit andapparatus in accordance with claim 1 further comprising switching meansto select the circuit input into a normal red and green wire telephoneline or into a computer yellow and red wire telephone line.
 8. Atelephone line monitoring circuit and apparatus, comprising:a. circuitconnector means for connection into a telephone line jack at one end; b.a bridge circuit including a first diode, a second diode, a third diodeand a fourth diode, each of which is a rectifier diode, the bridgecircuit connected to said circuit connector means at a location betweenthe first and second diode and at a location between the third andfourth diode; c. a first resistor which is a 1 megohm 1/4 watt 5%resistor connected in series to said bridge circuit at a locationbetween said second and third diode such that a positive voltage istransmitted from the bridge circuit to the first resistor; d. a secondresistor which is a 2 megohm resistor connected in series to said firstresistor; e. said first resistor and said second resistor connected tothe base of a first transistor which is a high input-impedanceemitter-follower; f. the emitter of said first transistor connected inseries to a third resistor which is a 1 megohm 1/4 watt 5% resistor; g.said third resistor connected in series to a fourth resistor which is a1 megohm 1/4 watt 5% resistor; h. said third resistor and said fourthresistor connected to the base of a second transistor; i. said secondtransistor connected in series to a fifth resistor which is a 1 megohm1/4 watt 5% resistor; j. a third transistor which is an emitter-followerconnected in series to said second transistor; k. a sixth resistor whichis a 470 ohm resistor connected in series to the emitter of said thirdtransistor; l. a light emitting diode connected in series to said sixthresistor; m. said sixth resistor connected in series to a seventhresistor which is a 22 kilohm resistor and which in turn is connected inseries to the base of a fourth transistor; n. the emitter of said fourthtransistor connected in series to an eighth resistor which is a 10kilohm resistor; o. said eighth resistor connected in parallel to anauditory sounder; p. a voltage source connected in parallel to saidfourth transistor and said eighth resistor; q. said bridge circuit at alocation between said first and fourth diodes, said second resistor,said fourth resistor, the emitter of said second transistor, said lightemitting diode, said auditory sounder, and said eighth resistorconnected to the negative terminal of said voltage source; and r. saidfirst transistor, said fifth resistor, said third transistor, and saidfourth transistor connected to the positive terminal of said voltagesource; s. whereby when said circuit connection means is connected to atelephone line, the telephone line monitoring circuit and apparatus candetect if the telephone line becomes inoperative and cause said lightemitting diode to provide a visual signal and said auditory sounder toprovide an audible signal if the telephone line becomes inoperative. 9.A telephone line monitoring circuit and apparatus in accordance withclaim 8 wherein said voltage source is a nine volta battery.
 10. Atelephone line monitoring circuit and apparatus in accordance with claim8 wherein said circuit connector means further comprises a pair of leadwires connected to a cable which terminates in a telephone plug.
 11. Atelephone line monitoring circuit and apparatus in accordance with claim8 further comprising:a. a Class II transformer with a 9 volt DC outputconnected to said second resistor, said fourth resistor, the emitter ofsaid second transistor, said light emitting diode, said auditorysounder, and said eighth resistor connected to the negative terminal ofsaid voltage source at one input location and further connected to saidfirst transistor, said fifth resistor, said third transistor, and saidfourth transistor at its second input location; and b. a fifth diodewhich is a blocking diode connected between said Class II transformerand said voltage source.
 12. A telephone line monitoring circuit andapparatus in accordance with claim 8 wherein said light emitting diodeis a flashing light emitting diode which modulates the signal of theauditory sounder as the light emitting diode flashes on and off.
 13. Atelephone line monitoring circuit and apparatus in accordance with claim8 further comprising relay means energized through a fifth transistorwhich in turn receives its energy from said third transistor, to therebyconnect the system to an external warning means.
 14. A telephone linemonitoring circuit and apparatus in accordance with claim 8 furthercomprising switching means to select the circuit input into a normal redand green wire telephone line or into a computer yellow and red wiretelephone line.
 15. A telephone line monitoring circuit and apparatus,comprising:a. a circuit connector means for connection into a telephonejack at one end; b. said circuit connector means connected to a circuitmeans for providing a positive voltage to a resistor means which in turnprovides a defining reference between the circuit means for providing apositive voltage and a first transistor means which is a highinput-impedance emitter-follower with a normally positive emitter; c.the first transistor means connected to resistor means which provides adefining reference between the emitter of said first transistor meansand the base of a second transistor means; d. said second transistormeans configured to act as a switch and to provide a driving current toa third transistor means if the telephone line becomes inoperative; e.said third transistor means is an emitter follower which energizes alight emitting diode and through resistor means and a fourth transistormeans also energizes an auditory sounder; and f. a source of voltage toenergize the circuit components; g. whereby when said telephone linebecomes inoperative, said circuit means for providing a positive voltagebecomes inoperative to thereby cause said second transistor means toprovide a driving current to said third transistor means which causessaid light emitting diode to provide a visual signal and which alsocauses said auditory sounder to provide an audible signal.
 16. Atelephone line monitoring circuit and apparatus in accordance with claim15 wherein said light emitting diode is a self-flashing type diode whichcauses the voltage to rise and fall across the diode and which in turncauses the audible signal from said auditory sounder to be modulated.17. A telephone line monitoring circuit and apparatus in accordance withclaim 16 wherein said voltage source is a nine volta battery.
 18. Atelephone line monitoring circuit and apparatus in accordance with claim16 further comprising:a. a Class II transformer with a 9 volt DC outputis connected to said telephone line monitoring circuit to enable thecircuit to be used with an alternating current source; and b. a blockingdiode connected between said Class II transformer and said voltagesource.
 19. A telephone line monitoring circuit and apparatus,comprising:a. a circuit connector means for connection into a telephonejack at one end; b. said circuit connector means connected to a circuitmeans for providing a positive voltage to a resistor means which in turnprovides a defining reference between the circuit means for providing apositive voltage and a first transistor means which is a highinput-impedance emitter-follower with a normally positive emitter; c.said first transistor means connected to transistor means which acts asa switch and causes energy to flow past a point in the circuit if thetelephone line becomes inoperative, which energy activates a lightemitting diode and through resistor means and additional transistormeans also energizes an auditory sounder; and d. a source of voltage toenergize the circuit components; e. whereby when said telephone linebecomes inoperative, said circuit means for providing a positive voltagebecomes inoperative to thereby cause the transistor switch means toprovide a driving current which causes said light emitting diode toprovide a visual signal and which also causes said auditory sounder toprovide an audible signal.
 20. A telephone line monitoring circuit andapparatus in accordance with claim 19 wherein said voltage source is anine volt battery.
 21. A telephone line monitoring circuit and apparatusin accordance with claim 19 further comprising:a. a Class II 9 volttransformer connected to said telephone line monitoring circuit toenable the circuit to be used with an alternating current source; and b.a blocking diode connected between said Class II transformer and saidvoltage source.
 22. A telephone line monitoring circuit and apparatus,comprising:a. a circuit connector means for connection into a telephonejack at one end; b. said circuit connector means connected to a circuitmeans for providing a voltage to a resistor means which in turn providesa current into a first transistor means which is an emitter-follower; c.the first transistor means connected to resistor means which isconnected between the emitter of said first transistor means and thebase of a second transistor means; d. said second transistor meansconfigured to provide a driving current to a third transistor means ifthe telephone line becomes inoperative; e. said third transistor meansenergizes a light emitting diode and through resistor means and a fourthtransistor means also energizes an auditory sounder; and f. a source ofvoltage to energize the circuit components; g. whereby when saidtelephone line becomes inoperative, said circuit means for providing avoltage becomes inoperative to thereby cause second transistor means toprovide a driving current to said third transistor means which causessaid light emitting diode to provide a visual signal and which alsocauses said auditory sounder to provide an audible signal.
 23. Atelephone line monitoring circuit and apparatus in accordance with claim22 wherein said light emitting diode is a self-flashing type diode whichcauses the voltage to rise and fall across the diode and which in turncauses the audible signal from said auditory sounder to be modulated.24. A telephone line monitoring circuit and apparatus in accordance withclaim 22 wherein said voltage source is a nine volt battery.
 25. Atelephone line monitoring circuit and apparatus in accordance with claim22 further comprising:a. a Class II transformer with a 9 volt DC outputis connected to said telephone line monitoring circuit to enable thecircuit to be used with an alternating current source; and b. a blockingdiode connected between said Class II transformer and said voltagesource.
 26. A telephone line monitoring circuit and apparatus,comprising:a. a circuit connector means for connection into a telephonejack at one end; b. said circuit connector means connected to a circuitmeans for providing a voltage to a resistor means which in turn providesa current into a first transistor means which is an emitter-follower; c.said first transistor means connected to transistor means which causesenergy to flow past a point in the circuit if the telephone line becomesinoperative, which energy activates a light emitting diode and throughresistor means and additional transistor means also energizes anauditory sounder; and d. a source of voltage to energize the circuitcomponents; e. whereby when said telephone line becomes inoperative,said circuit means for providing a voltage becomes inoperative tothereby cause transistor means to provide a driving current which causessaid light emitting diode to provide a visual signal and which alsocauses said auditory sounder to provide an audible signal.
 27. Atelephone line monitoring circuit and apparatus in accordance with claim26 wherein said voltage source is a nine volt battery.
 28. A telephoneline monitoring circuit and apparatus in accordance with claim 26further comprising:a. a Class II transformer connected to said telephoneline monitoring circuit to enable the circuit to be used with analternating current source; and b. a blocking diode connected betweensaid Class II transformer and said voltage source.